什么是处理大量Promise的最有效方法?我想出了2种解决方案,并确定使用bluebird的promise.map的解决方案2更快。
解决方案1(每个文件约38ms)。
readFile(file) {
return new Promise((resolve, reject) => {
jsmediatags.read(file, {
onSuccess: resolve,
onError: reject
})
})
}
async readFilesHandler() {
console.time('readFilesHandler timer')
const fileArray = Array.from(this._fileSelectInput.files)
const tracksArray = []
for (let file = 0; file < fileArray.length; file++) {
await this._readFile(fileArray[file]).then(tags => {
tracksArray.push({
id: file + 1,
title: tags.tags.title || undefined,
artist: tags.tags.artist || undefined,
album: tags.tags.album || undefined,
year: tags.tags.year || undefined
})
})
}
this.dispatchEvent(new CustomEvent('tracks-selected', {
detail: tracksArray
}))
console.time('readFilesHandler timer') // ~38ms/file
}
解决方案2(每个文件约32毫秒)
_readFiles() {
console.time('_readFiles timer')
const fileArray = Array.from(this._fileSelectInput.files)
window.Promise.map(fileArray, file => {
return new Promise((resolve, reject) => {
jsmediatags.read(file, {
onSuccess: resolve,
onError: reject
})
})
}, {
concurrency: 5
}).then(tags => {
const results = tags.map((tag, index) => ({
id: index + 1,
title: tag.tags.title || undefined,
artist: tag.tags.artist || undefined,
album: tag.tags.album || undefined,
year: tag.tags.year || undefined
}))
this.dispatchEvent(new CustomEvent('tracks-selected', {
detail: results
}))
})
console.timeEnd('_readFiles timer') // ~32ms/file
}
有没有更高效的方法来实现相同的结果?